SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce64553c5dd27569a4d79ef5137021133b8d5067396d7304e587987a46e616b1' 
  AND token = 'vZmG2H2zZlEuTqwE0JWOGJg9rDpF762PSyedSSl3WTc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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