SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f71debd9e88d666649bca077325eefb5798d5bd3de2e3130a06f3446ba217d42' 
  AND token = '6NX0r/+90t2jZ1Mz79LvOhMyoB+pb2z0Wp/VV5YihQo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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