SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e9d2bee181bebf9a47571c5b2bedc76f67da040dc33c6078c85931eadb4ad448' 
  AND token = 'x9hEhlWSmzF5jsKLxdEIsuqXyCBxa+UAAWAXDOMmzhg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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