SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '53af39c96bb241d7795ef804cc8007d78a5f4368b7267e9076c7a8b498f84827' 
  AND token = 'PFhZJxMu7uamhUbJp7gfKZQJpd5IOoqOxWUxnBTSGpc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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