SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2966bb66d7935e906d4ccc39997b752f9a203a87690982629c9fc1b4b4053a15' 
  AND token = '2PcFZMpuq8NnhUKkJAhEwgSCArE8BTWNfgheDGPsv7Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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