SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0bb38b5b5b5a88926885e9c361efa60672425c3bcdd26989e992101c62009815' 
  AND token = 'CHaA6vKEmngHyvC0jMc26ZY47PxZP1AuKRVoxnaDGy0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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