SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '629221ff8e3b6275ca93ef3e5d3944a329dea5c9475aefe67e8cf60908404165' 
  AND token = 'bFTxbRYfmDn/BZ8GE9qfzf+YjM8ZzmEusTMXv0lJ7mw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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