SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6cffa1b1d135421469cf7f81a28823bf6ea1c5e713b8bc6e3886421175d7b8d6' 
  AND token = 'FfOMzQoaaqPvr986++ZsT3P8xC4vFc4Tp7tOZUTEPFI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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