SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d959e005ae9ba1efe1ad01d126fff6507c4c09a82e59da07501ac530bd41fc9' 
  AND token = '2NY5xtOfn4WJry8C4mwmIxCYjois8ME77tHivjVBowo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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