SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c5f669d995a696fd6cb9b1ead72e480bf96d323867dbcc4e5c7ca2b7e1fcbd65' 
  AND token = 'ROvQekugkuF8gS6uQPIBKYYn5RLHBFQAGJm7QcitvK4=' 
  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"
    }
  }
}