SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd423bf84e79a318afb78184b0c1abe6fe24d75eec5de64939dbef21f5f85a24' 
  AND token = 'c5/118wCnM3FDZp/UTksEZmoirY+Wu8bRvcSAh7vaRU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00054

JSON explain

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