SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b2ca0e64439e036a1718b687c4599ceab0fb5c365b3d84c710de258b90ad08d9' 
  AND token = 'e0Ci6zviRPK6kzu2CviTDkYE6TP8yC28s4dxW00SW4g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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