SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e36ad7d496e51c5c4f944dd02aac707c7105c82fad2d0d163d9744e0a9d94306' 
  AND token = '51dtGLSXo0oDHtM053+zRWWcnCaMU6pxTzIfEEnXc+c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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