SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '878ce881822ad349807c073504a4eb3d94096ab32bc60bd103eaad72c681af71' 
  AND token = '/l5ASGZfkcx/KBh/ZEpn+V769QfSmZQZER+TPx5QO6w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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