SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ea73d900c227e65a681e79faa63bafdce8e1aef6213182cd3f6f2a96bf1ff075' 
  AND token = 'dZW2AzBZ2n36gI9sYOQbLiT0xzmMbJmVbpNfdsgSPHU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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