SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c98d91116e6bb118daee593dee4254045dcd6e7ce0415fb0d054da71020f3453' 
  AND token = '3ZecnOlrXbhfU5HrNY91uovAspCPTL2E80J8j04G5Iw=' 
  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"
    }
  }
}