SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1bc3c80c8925edb34b397d03311e2adcae30eb4c355612bd8643735ccf295f82' 
  AND token = '6kFeEhshzwwkB36G6+6YI0ZlFWWLUJkuMHKvewHNOvA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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