SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad5ddcdcfb7b5c13fedd1c1a77884168eae527c30ec2021dbc46e5a4abc82775' 
  AND token = 'JxV75NwptAQV+6nDhBcVPHFyCW92+vMVmabgCJIvF0I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}