SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a0bdc7fdc11aaeba839cae45e94e3f8f28a5f20bbab9d651571a31417ba38072' 
  AND token = '3YjumTcdnO7NQJga0gRzEIAzaYAqOGMvbENQU/RO7JM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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