SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b7942edbc3408a3d2dfba0d78fd2e53aa3bcc87dc215cca0d1c2295543c5248f' 
  AND token = 'ffdjk0rR0rOYJN/DK+waiYRxAS8XNXllMV7BG8MB8oo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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