SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e272befe28b4cb018521204d5d52196cfd2d45c5a7bb151dacd36deb4b35efb9' 
  AND token = 'cfiI3txdFv5AB4f0KWOqC9sGk/0vcool1vTCXET0yRs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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