SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '505866487d2826f5572d83af9d3eaa91f1fadb509326ad2b19710b74fc89b0f0' 
  AND token = 'pQVl5yLx5eFQhw/g/PFs8muqD4cD5fBvgVICZFPJJ/g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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