SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aa9f3a6235e479f95815870e7b30c959dd5efd16f29346b5ca6b6a766fe451be' 
  AND token = 'zW4G3LzbA3SIOeMpVBsglyXPg2lbsZlnIV/vBALCQW8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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