SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12585512a12b0d241159e08e79a324d6ab12986605157e3b778b026ed513da91' 
  AND token = 'hEwjvseCEB1wDShLsypQ8rOk7SlKBzJrljJEEryDTH0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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