SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f20a8e770e8c47ca1eab33d424f3991d49055565732e9ad646ebb70be892548b' 
  AND token = 'gPydFUtnBE6V+x3ycgDZ6CA68YgmWySZeckC00hZbtM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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