SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '3316c4d15fac3a168e9e330b55b078829eb6f049d4d5925b287523cc6401b47c' 
  AND token = 'R3FDtuwOifyT4AclsY6ej4w8eYzcgtACIhu/3HhVHOQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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