SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7137d49add4cec528271c3d9e0844e763c8bc3af240b9a5106b8361020ccb3f6' 
  AND token = 'K0PTrBbv7cpDIdAW+Y0HvIV69vYPrUuGop5AiJ27IKk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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