SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '395ceb7d4c3954e5addf233647ed8358d52179dda34e85e9e57670783131d3b8' 
  AND token = 'L2uTW5F2MLSOVe3Ff2XbUpcxPVt0xG4COLaXvFRdG1M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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