SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '726fed62efcd778262a0af243541863d3ce874b1f6c984209c3508e0b10865d9' 
  AND token = 'nBLErpk4lpwM4ZVy6C3V9V2EDscjUJ4r/gP0tHLhjFo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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