SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c08e06dbf5c4b644fe2cdf99b5240e2027569ec556205f4db0278adcf83da87' 
  AND token = 'ypSMeLaDAAeJ+Vk2dtszoLRaSQJ7wHhtO6RtizR7Kyo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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