SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91b8cf7c4eb727a42a33ce3e6c97d9fe851d7d17987281015adeddc5339c2f9a' 
  AND token = 'B+npS68VVJCJGqz694glKyrUJg4dfrHvlSIy2ysYbhw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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