SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2dd8bc3c602995a32bba90590459cf76481624e73240789e4e11f888d6d0bf39' 
  AND token = 'b+Rmf/4Vx9TxouWSfrraNNZcCYgEIkID62Oah861jfw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}