SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37a5615f861104da882b4c3fb3f1d539a42943ff2fbbff498ef35f34cfd6f0da' 
  AND token = 'Z9iz79ArJPpu3tuXAktqkPpBbo48gBKeSy3MiIczps4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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