SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6883f520b9832a1b4f38b72b09029a7101d99382380a6f2d8bd2a42e03d2922f' 
  AND token = 'mWeOI1raqxFqXxpxvf2PfmHw/c5yzLdxvEMfTITtCF8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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