SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'df71a11edaf3a167c3d02ca2e07e946f48dd9667b179fcdada42a2e90cbf5b5a' 
  AND token = 'McckqXc5R3YtedaxBgTdRNTAA51AgA7+ZPlqEgjWftg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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