SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df5968e5aa2a13b091e8f137723c8850414e8ffdfdfc2e413940952c7a6897c5' 
  AND token = 'vdBallq+JYk8UTJR+IYT9qcPVfsfhYZuNKa2gNYhx2c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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