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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8dff4a4434c6732ef313fd30c0742392b843c1301835541af1619da1d83017c3' 
  AND token = 't27uAV3mMl+GFH5hrqnp/883IrFYuT39SlEmNx5xM80=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}