SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '50f18109e34ab3a40ba1e7259a95266c5a5b431e823682774afb6db4475fc398' 
  AND token = 'VunzgbdsR6MmyUvQFLbX9K+8GfvlP+B15m0oC3hgV0w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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