SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7eda7106d9444c43c8c87a38c89bd03b4aef4a26bea8d3f0e43d3edad4004a83' 
  AND token = 'VMBC9oDrxmruHitfXEZIaDnfzMcnU8JnZdbsmeP6nzE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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