SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a2b9725352c9d9297a8007640d9e764e789ffa6767e483dd434469348e8e4f0' 
  AND token = 'ZsWWLtsBZjkdKfxMrtnJYJL3JkuYyKXhwek1lEPkYCM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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