SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7761f41c76e8ed4170ecaaa559967d84215c25c4420dfbccd5451b613bbf9ebc' 
  AND token = 'sJrfR369pim80l6mBpDlRWewrhfXbMHwrWiC2q1/zTY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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