SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1434c44f6003aa631fe944175260454f4af0221e6702e6f933a58a5cdfded0fa' 
  AND token = 'o9qfxdYSgsetbWvMv+Slqc9mfX23ovuYXvrjYMxtI0s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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