SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b17287947c0d0f074e80ec835f495704641526d88d1fdb99e97a7318e167582e' 
  AND token = 'U3cEiFD1tSoKxm3Dc1n1dIbbilk5tzOihQ4J51PujDo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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