SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'aab2f34d3a3beb11659fa1b32b91c45ba202411db084700edf3474f8dc2d46bf' 
  AND token = 'MzNSu+2BQjjpfHdzQt++zlq8Tas/HDpr4igQF9Z6TtI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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