SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7e578a48b94a1217bd672a1a19a9a76c46f0690b095add8e0c8c6d46994e015c' 
  AND token = 'MpUKFDRMlQZqhXCVBTZ6M5NBPh6/bDjqKicsCaplEWU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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