SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef69b8bed0bfa7acd655a14160b941d55780e12398f1ccb2c7ecad5dde962696' 
  AND token = 'oj8xcNJk0c+FVg/LEXQlM1d3+i3z8vj/WFvk/qgv1Ac=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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