SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a567d3ec6605b93bd6598119b66e0ce350c5bfa5fd354cc87c63b55701316a7d' 
  AND token = 'S7leba8kwNljWfbOxoaijrCWKEiENwuTeHd1pUWRjV8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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