SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '012540ff3f9a75a1ed16c3e84d3699d7a08d353ca4b0cedad066036297c2dd5f' 
  AND token = 'jMJhlJlRNikjcJzr1IFso9BcYWZn9hgfV4DLzpENpUM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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