SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'aba49c34364d97838f94dc95b1a730e570d2ea795ba4ff1081f049314cbc8182' 
  AND token = '3RE7kQs2AmxxH5NvgBJQJFUy84Id00KqMWmFfor4/jM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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