SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '90bb29717360cbb18e1573190d450a722255cf0262c6eab511c37e5974098cfd' 
  AND token = 'piR+0HTlrSuH13efjsFDVFuoIE6abHU3sWp0kuTOGjQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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