SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '134cf27ee065b253732d682f3318af35d971716d9a40ecf90aeed2979ae253c9' 
  AND token = 'x0FvGAuP8WQPmcKcqiVSCibqtlOUQLZZl7lDgAVjPmg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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