SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f640b2c1f8ad395956e40147f95912f793a903202578b9f441d54ca3dfb179e6' 
  AND token = 'TbvKstH0783IJkrFEzJhKWIlUWPo7oqLPF3mSuURFPo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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