SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b43af112fb3f82414c07f9335675ff08aaae3ddcd9596c4f847896c94733ec3' 
  AND token = 'TnwvjdusqPWmyWicfyfEFDx8sxvcKHQrp2iuKx7+p7Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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