SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a64d331a93c22449aadca7ce300f70c1b5464db4c40501efa198724f79d2ddcf' 
  AND token = 'iqmAKbPyFesOpcS6ivxL8FGyyA9KlePw4jFZvZPGlBQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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