SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec8dfd8ab559fc83f2838a1c8b1f23dd2274b8a27391bb5a4bd6da7b7e049fd7' 
  AND token = 'fyVCQ6QelzHbPRVcG5Y57Ksr/QoJwFcuhLRZDqbB7nE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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