SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9329f6a975dae51c1e5ea2a7e681d813921235b5772d7b115bd7ec74d6ed883' 
  AND token = '307F8z42QJmBIgFAbHZNSkQ3G3/AWusH4fNw+Olbpfo=' 
  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"
    }
  }
}