SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b08f4ee343b1933b0a9cc260880a824851ac95d191a8492d82663dfe8e055e8e' 
  AND token = 'TQBYKgsIljiK3CSp5iQP1xqwm+aOPpzYKqnMIbrXwvQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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