SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '94795370de326bbd758cf27c7bfede034a50ac36f69d9a0aa6d2b125b112c45f' 
  AND token = 'sdbA/FdLLh1fkzTS9ZhhrSOhMyRXztV32TsQWTZFzOk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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