SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '30dd7ea4dd0762b7f38049105526707cf2394478c1e7f227eff927049e478658' 
  AND token = '5DugPOJhYb09JVgeoCUjSY7XJLTJI89ef0TI0vFBjIk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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