SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '76007062113404692e84abdc1bd7bc4962d085a5e47961d495232ffd38afd99f' 
  AND token = 'Eba0W0vyPUimiyJTpP/dkSvqEZK+iX3HnxqijcYkF04=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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