SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '830cbb681a273430f53d397307d6b8fbd23602ded64b6c848d0ccc579db94043' 
  AND token = 'YyTwP8k9oDC6UJ/Ix5CYW/l7rNC6Ls1nQogyLP0/pmU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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