SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9fb53b28e92247bb81a814c670483ce5e24e42027fa7a3ba165cd7a13dc888f5' 
  AND token = 'MzCDNWG9pVe7eg81oLZ3lFfpRTIafZJykWvwUBNQcIc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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