SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1d40dd445cdd3cee255ba68e72f92526f538aecaf165f80345a0347fa704e2a7' 
  AND token = 'F7kXwuw8hoAHKGd+dTlFivRCWPk3zxPqOZVEgnzNeHo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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