SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3a29597a0c1b1eee10eca527629764bc42add82317ab1666ec7c5a90cb0cede' 
  AND token = 'EXqWxglYnOPANhsOGLhQghJoYS28Ryk8v04XDGDIv4M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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