SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '17a50bea0201db62e7e872fd99c857927503e7e697521758c0066f91807170af' 
  AND token = 'LVJIqd1hRa8wVbLOtYpubyc2erSsojMkk9PW5IVC4Zk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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