SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b5b4a3366f6b9050109793356b201234d6c1c2ab6147c0c38856d01d01acf95a' 
  AND token = 'bDP4sv7ZvX9xJPRwfm2lcrTrXkqFXTg6V/KKFKVz2sA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}