SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d7bf509812c6c83311fc9dcd42b554d5882d6c25f0282d1f71df6449d69517f' 
  AND token = '2GvgeKi7E+AGDtauOjIH3Hjs/V9xFENqmCL0se6QiKg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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