SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c4144b8ae6926e12a116219c992f1755876195b6aff65e0222e6234063defee1' 
  AND token = 'sVFwWivWokG11KXi3T69Z8VXVA01jyM3L9cWMikFs94=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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