SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d63b8009327020d97c4473f820523ec61ea514bbecc177aa0097ed377c159a8' 
  AND token = 'N6WIstEBgG9bScKN93uhvASmD9wt8BgX7C/KclTeT2c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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