SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ae2c675c232425fe07b16ebe132696f91f5e7c311c3a08ac5832ebd7daae621' 
  AND token = 'UbBi4PsocWhIIF2vISmB/x9dvYExxjvonhKGuduQo7I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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