SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ebe06b2d62d0fa077a3809b3094c918e470fbf62b63d5adcf2b1a2b1f74adce' 
  AND token = 'tJoqckjgWNL+X5BhpzzZNfr6xeV1P4AwXqxK4UkBFhI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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