SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '400cf7069ccf2c3d1c753e2ad4066dae740dc03cf67dde81412435695e0e5512' 
  AND token = 't1VTmMHOzbR0aeazHnpLll2dxi5GHPEsoqugyKPB5ZU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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