SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '11a3c6317be78fce71a06422f4f5eb96e36869f75d2b3f5b1e1c8c752f0ad04f' 
  AND token = 'WAB+HQ4m1oaf2ggmeXJIYaYPTvUMufS22w1tIatvgO8=' 
  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"
    }
  }
}