SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4b97fcf04edeed95c8197d486a4fd1dea138563fba22e706b6d26d648fa067a' 
  AND token = 'G/MlY8dZ8dpZRSnniSMuPlmhWgKEZVYmUo8jCgvmLMM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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