SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '64668feb69fc10248da82541e0ebbebcd0e3994701791a7f8123fea771dc9ead' 
  AND token = 'UV2+NkKYmkBfNo03tdphfgh0Y+cSJeDUIo1RaNVH6z0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}