SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f035eafda2143331a933ca07f2b14a627dd4b299e0c4b9b89d8e44873d1c664' 
  AND token = '4UXXgjzKjrm9OFDX0DGZtao/H+IHadgrFCnmlq/rEu8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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