SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c6c807978ee431851b4afd77727b4b22a536ca1aaac173aec2040448aeaf775a' 
  AND token = 'Nd4SC8zS4BJ9q1tcT9DrWdrWiwFfC1fJkMGU/MYKRtQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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