SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bcee88a71f9ed9b3aa701c52153d111fafe14b383e1d4ccfdb9de5fcbdc4716e' 
  AND token = 'OFxCerykbLhXKK8WU31/CROsd7Ycf3XJJQd7ZVnxfpg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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