SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9d80b66c69d077aff5dee626bc6685bfe16793a80de692af56815ddc8e4c522f' 
  AND token = 'o1+4yM7Hm7M1t7vevajvMAYq86LH3wsK19qXThgsQSg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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