SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0b6bd447154102b7ee4b5c4a9d5fad18f75b9e6c26ea88fc57fb7bc542731da3' 
  AND token = 'uWqt9fZpCbQjepgdLd/PPBK+MduFZKJgsvO2VEjYocw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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