SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b7c3df4c350bb516898d551f6f1aac7d93996b808ee48cc92bfb9fa5948e31a' 
  AND token = 'BgZzsXXFMRRH4dhwkO/2nYtUPtrlGwsulG7/UeHP3Vc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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