SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c95bb795e71ef03eef8dcb518952596f2a3b756e956d734c27385f3d4841c92' 
  AND token = '8yUQiGOy0n3Fif+e+cjCp06JW+3UG/uzH6h7AyrIkWs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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