SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b4a65ce456e643a3dcc8170f107db2b9e978b28464cb5988065dd6e8602e1c59' 
  AND token = 'JKmPquh6xXFYHwsYRXBbnBtKd+LVJSOIYBRp+Y+oxlw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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