SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec6c953e4f81e15532e441c8b06cfbe0834e9720aaa1057de7e829bcf491d417' 
  AND token = 'SUWmxJ2+jnXyWAFWR7wNPn0YOLhgzTVq6wJj2KalJlM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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