SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7dc0696ca74480d37c712e10dc38e5a6b3c877d9441c975d498722d7106efc71' 
  AND token = 'L3mCvaWr9C8u9R4FtmlabhWvnOxBM7zPJcbssHgwqVY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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