SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b13c4055cffa13a30e791a46f3421dd194f09b1720ee76f0f0a75a09552d1da' 
  AND token = 'VoIdrfauThCWfrRjD++2ITdcVp7uxYjYZJcbIYCxY7I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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