SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7af06e15bed6b38e15f2bd593b0788c42ee49f7f431b1681204669996364f5a0' 
  AND token = 't/KtspCnzaKSwj+cdRGlI69kK9zwo/DpG0VVnoEVGnQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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