SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c9d6f9d7d678b32602ee003c1cd4bef324f647fddac3a58924f662817898ea8' 
  AND token = '/JECpTu6VHbowjpRWJTqIObQb1xUQh6al0cUVV+7SVo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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