SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ae55d2436cde317f1f358c196a6e58772c1c82a00a2f41f78a562d0c104f5a3e' 
  AND token = 'DcCms9WFqBOQzv/CyjtqxwTeRZa/ZL4X2NmrqtEVgIA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}