SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '9b7f9e20df10a1ba891869ad2b3bdc8d3fd0923e7fcc6996708b4b80daf9ebdb' 
  AND token = 'hha/UhKZUp3LthR+3VrLBNVQU5+BMN+DZJnRj+G4qog=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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