SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b0824329ccc9e17304dfdf3c28fcb55f30c2c2d40ad7ff194688b95da0c66c73' 
  AND token = 'Pf32atupAvVpy9i4ddxhNFhJ0vgvnQkk5ZlvzGB+ie8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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