SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f73063c1bfd31638682d3a66c0e200dcad42541965be119a26eceed72f11b5f9' 
  AND token = 'Pqx/B3Roeg79tyZXXwEdg13DCeb+Hitsns7DgqRt/iI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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