SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83ef0f33753cb1c782bdf465e40187c622d4f9689fb0f3356d48d0c1dd9ec64a' 
  AND token = 'o+roUJjLeiovZGOiEqmD/l4FWPvWNoREPorVnvAfQc8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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