SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '19e994e9fe916df290dcd85b1f6bb05520bdb9f6c29798ceb70e787a2c4a209d' 
  AND token = '0fVoppjq2YKwgZ8D3vXAqyv8D05vmqvv+jqU1FGM/h8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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