SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78bc8c47643d0ecac8b230fc42b01c3ae4de73af36e9189c48e36132e9db8fdb' 
  AND token = 'j5mCIOnww2LA0pYMpOqZnbfxMLjHETtDQG8QnsqQ6MI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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