SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f8e5b685dadf7d2daa00ae61be603e4675dd35a16f0974863c5ea9a8d0e2e338' 
  AND token = 'dBaqSrnbYHYaHamd9a0DJNLHZLJAkFpzMoBNeRMDcjI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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