SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6de1510168893760b22fc57d0d16a29f800a10a2bb579caf93f365b4b630cd51' 
  AND token = '53rQbOoHmZWOEihylo4DbTmyK1WsuSyDp6SQZxe/SrQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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