SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'becff67639c0ddd2a797b3a8839399aed52e43433f98232d1b0719ef92dba1a1' 
  AND token = 'VeQN+/kbfzaom9JwGzD8Q93mT5skbnDSXVoRdf/FEUc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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