SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'f341a267f819e79a9f6ee73752566e639a2dae85ed4afde48f63b0bd3e45ff72' 
  AND token = 'kJ74QPyG7olpuoNj7n0CBlk7qP9or6uHDUQEv+JxwEc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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