SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef6210576bec4b6cbec0055e7c638a14215b58c580e25f1730baf608adea1429' 
  AND token = 'NZ89mI/LKlNv5O5Y6P6Xw3K+I5SlSWoiGxnYo0Tfkt4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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