SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8dcf0d5d4c9d663f6f080d8ccc91917f0539b2bb3d555b7b16d3ef3a4b926334' 
  AND token = 'LZecDPAJXMvDY5ftPIEuWMuaOttRxDBAHvjHNDuBkes=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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