SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e6f5155435a71bfd2531155b98b3ca7c4a3afb7ae342567fd491624379277ad6' 
  AND token = '7JYOzrdBemELLn95i7KWrUXkZlaq+pgILjRhV8JODbM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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