SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec521f56d9850ded6542df2d6047b2f6991bb70230537ec984f1ba80c1f33282' 
  AND token = 'y7u+Hmu0wt+GWK3v+EenXfoqLIxXz1ugYK3lY1zyL3s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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