SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '7cf052c16d4aa0718f37390ca97aff75ab5f9b4d139605a21cc967d73f952877' 
  AND token = 'Z1N4jz/Q7LxyrWu2yiXr8MTKGSqZ/pthwfCapaMDn8U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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