SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b2dd0303bb0b50a8a10798055b243fe5163c1655245f3339dffb2bc70065ecc' 
  AND token = 'GHgYhN5CgNHla7zwsopuF+GtCSjBdZpEWvNP+c9fWHo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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