SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '63a0cbabb762f321870a02dca318f1198307970035e74b98fc191a32726e96f3' 
  AND token = 'UuyxRgggO2PUKRZF70N9DyRBTkZPjTg4NeilKXhLyqc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00059

JSON explain

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