SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a73e7c5197710fd93c9f4606ec493b8c7e5512f5e7695eec7effdeda356bac0' 
  AND token = 'nZud3cnzh1nFNJOx3UOutazoLdnalALRvUg/ny7r7Hs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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