SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aaa601eccdbb8f5499ed15e9e2f776f689bb0ccd9d36ceb63c985ad10aa37239' 
  AND token = 'S7idJBusMLpXX9hvaYm/4ixwpqb6KJnI9HnbyVRzKpk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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