SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd76190be50b0652f1e12bf1f5d21b8ac2308ebf8c4cc5d68545860aa61d964b7' 
  AND token = 'rgdYkZmlMItqpbBBCM/9yzDbWWJr15HpGkNDp+mMskY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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