SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b1ff7cef6b69aa6cead16cd6e711d44eed775561417a4d31074e7c9ff9cd5da1' 
  AND token = '4Cj3mdAo/w7wzd/Z2BalU5MYEyM4bUlYSkLPuOw1sbk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00095

JSON explain

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