SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '16d3a18017da6699192860fcb4d887a07f59f3f07daf45aefafe10007b5e61db' 
  AND token = '7S3Eg8BCCqUX74YLKBGA/bepjU2nPc+dFFi5/8nps3E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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